Wreathed in Flames

Dr. McNinja: Oh, alright, the ninja poseurs out there now? They light you on fire? I guess I can spare a sec to get nuts on some punkers.Dan McNinja: No. I lit myself on fire. Anyway, I got in pretty deep, and now these tootlepuffs are trying to get me all the time.Dr. McNinja: You. Lit. Yourself. On fire. Why did you light yourself on fire.

A character has the ability to set their whole body ablaze with flames. Different from Man On Fire, as the latter trope involves that person being harmed by said fire. Because fire is awesome, this makes the character automatically awesome. If they can turn it on or off, expect them to enjoy showing off via Finger-Snap Lighter. May be a form of Battle Aura. Flaming Hair is a subtrope of this, where a person can only ignite their hair. By their nature, the character is not harmed by setting themselves on fire—they have the Required Secondary Powers .

Firebirds of Russian mythology (not to be confused with The Phoenix, though they have several similarities). Depending on the version, they were either literally on fire or just glow-in-the-dark. Most people assume the former, since it's infinitely more badass.

In The Dresden Files book Ghost Story, Harry learns that things work a bit differently now that he's a ghost. Sort of. When he gets angry, his entire body starts to burn, and it actually blisters him.

In 1st Edition the Type VI demon could immolate (create flames around itself). In 2nd Edition demons were renamed "Tanar'ri", the Type VI demon was renamed the "Balor" and its flaming protection was always on. It was based on Tolkien's Balrog (and was actually named Balrog in early editions of the game).

Pokémon: Some Fire-type Pokémon are covered in flames, like Moltres or Rapidash. Several Fire-types have this to a lesser degree, like Emboar (who has a beard of flame) and Normal Mode Darmanitan (who has flaming eyebrows.) The moves Flare Blitz and Flame Wheel involve tackling the opponent while in this state. The former does produce recoil, though.

Halo 3: In online multiplayer, you know what the quickest and easiest way to identify an employee of Bungie Studios is? They'll be wearing Hayabusa armor....that's on fire. This is a reference to a famous description of Halo 2, given by Bungie while it was still under development, "Halo 2 is a lot like Halo 1, except it's Halo 1 on fire going 120 miles per hour through a hospital zone chased by helicopters and ninjas. And the ninjas are all on fire too."

A simliar honour is bestowed upon those who preordered the game, but with red flames instead of blue. It tends to make them targets for snipers.

The Warcraft 3 ability Immolation, in which the unit covers himself in flame to damage the enemy (but manifests as a circle of flame surrounding the unit). The item "Cloak of Flames" gives this ability passively.

World of Warcraft: Warlocks get such an ability. It is also employed by mooks in Utgarde Keep.

City of Heroes has a Fire Aura powerset. It also has Thermal Radiation, which has fire for multiple different purposes, such as healing wounds... with fire. Protecting your teammates from damage... with fire. Improving your allies resistance to status effect and improving their damage... with fire. And finally, the only logical use of the powerset—causing damage to your enemies' resistances and ability to recover from wounds... well, you see where this is headed. The entire Thermal Radiation set is devoted to making your team into badasses through the precise art of setting them on fire.

Guild Wars has a spell that sets you on fire, and makes you faster. When it expires, you set everyone around you on fire.

Lots of examples in Kingdom of Loathing: the monsters Flaming Troll and Flaming Samurai, as well as the Flaming Gravy Fairy familiar, all have this, as is pretty obvious from their names. For the player, there's the ability Salamander Kata, which doesn't hurt your enemies but constantly recharges your MP; a straighter version is the "Burning, Man" effect, which surrounds you in enemy-toasting fire, but also burns you just as badly unless you have a special tattoo.

A "Body of Fire" spell in Arcanum allows you to engulf anyboby, including yourself, with flames, resulting in added fire damage and resistance, as well as burning foes and their equipment when they hit the recepient with melee weapon. Howewer, it's the hardest spell to maintain, burning your mana at least twice faster than other prolonged spells, perhaps to prevent it from being a Game Breaker.

In The Adventures of Dr. McNinja, Dan McNinja sets himself on fire to prevent lesser ninjas from catching him. His suit is explicitly fireproof, but we don't find this out until about fifty pages later, after he lit himself on fire again.

Axe Cop: Axe Cop can light himself and his team on fire to become Axe Cop Fire and the Axe Cop Fire Gang.